/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: BasicTestIterator.java,v 1.2.4.1 2005/09/14 19:45:20 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.axes;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.dtm.DTMFilter;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;
import com.sun.org.apache.xpath.internal.compiler.Compiler;
import com.sun.org.apache.xpath.internal.compiler.OpMap;

/**
 * Base for iterators that handle predicates.  Does the basic next
 * node logic, so all the derived iterator has to do is get the
 * next node.
 */
public abstract class BasicTestIterator extends LocPathIterator {

  static final long serialVersionUID = 3505378079378096623L;

  /**
   * Create a LocPathIterator object.
   *
   * @param nscontext The namespace context for this iterator, should be OK if null.
   */
  protected BasicTestIterator() {
  }


  /**
   * Create a LocPathIterator object.
   *
   * @param nscontext The namespace context for this iterator, should be OK if null.
   */
  protected BasicTestIterator(PrefixResolver nscontext) {

    super(nscontext);
  }

  /**
   * Create a LocPathIterator object, including creation
   * of step walkers from the opcode list, and call back
   * into the Compiler to create predicate expressions.
   *
   * @param compiler The Compiler which is creating this expression.
   * @param opPos The position of this iterator in the opcode list from the compiler.
   */
  protected BasicTestIterator(Compiler compiler, int opPos, int analysis)
      throws javax.xml.transform.TransformerException {
    super(compiler, opPos, analysis, false);

    int firstStepPos = OpMap.getFirstChildPos(opPos);
    int whatToShow = compiler.getWhatToShow(firstStepPos);

    if ((0 == (whatToShow
        & (DTMFilter.SHOW_ATTRIBUTE
        | DTMFilter.SHOW_NAMESPACE
        | DTMFilter.SHOW_ELEMENT
        | DTMFilter.SHOW_PROCESSING_INSTRUCTION)))
        || (whatToShow == DTMFilter.SHOW_ALL)) {
      initNodeTest(whatToShow);
    } else {
      initNodeTest(whatToShow, compiler.getStepNS(firstStepPos),
          compiler.getStepLocalName(firstStepPos));
    }
    initPredicateInfo(compiler, firstStepPos);
  }

  /**
   * Create a LocPathIterator object, including creation
   * of step walkers from the opcode list, and call back
   * into the Compiler to create predicate expressions.
   *
   * @param compiler The Compiler which is creating this expression.
   * @param opPos The position of this iterator in the opcode list from the compiler.
   * @param shouldLoadWalkers True if walkers should be loaded, or false if this is a derived
   * iterator and it doesn't wish to load child walkers.
   */
  protected BasicTestIterator(
      Compiler compiler, int opPos, int analysis, boolean shouldLoadWalkers)
      throws javax.xml.transform.TransformerException {
    super(compiler, opPos, analysis, shouldLoadWalkers);
  }


  /**
   * Get the next node via getNextXXX.  Bottlenecked for derived class override.
   *
   * @return The next node on the axis, or DTM.NULL.
   */
  protected abstract int getNextNode();

  /**
   * Returns the next node in the set and advances the position of the
   * iterator in the set. After a NodeIterator is created, the first call
   * to nextNode() returns the first node in the set.
   *
   * @return The next <code>Node</code> in the set being iterated over, or <code>null</code> if
   * there are no more members in that set.
   */
  public int nextNode() {
    if (m_foundLast) {
      m_lastFetched = DTM.NULL;
      return DTM.NULL;
    }

    if (DTM.NULL == m_lastFetched) {
      resetProximityPositions();
    }

    int next;

    com.sun.org.apache.xpath.internal.VariableStack vars;
    int savedStart;
    if (-1 != m_stackFrame) {
      vars = m_execContext.getVarStack();

      // These three statements need to be combined into one operation.
      savedStart = vars.getStackFrame();

      vars.setStackFrame(m_stackFrame);
    } else {
      // Yuck.  Just to shut up the compiler!
      vars = null;
      savedStart = 0;
    }

    try {
      do {
        next = getNextNode();

        if (DTM.NULL != next) {
          if (DTMIterator.FILTER_ACCEPT == acceptNode(next)) {
            break;
          } else {
            continue;
          }
        } else {
          break;
        }
      }
      while (next != DTM.NULL);

      if (DTM.NULL != next) {
        m_pos++;
        return next;
      } else {
        m_foundLast = true;

        return DTM.NULL;
      }
    } finally {
      if (-1 != m_stackFrame) {
        // These two statements need to be combined into one operation.
        vars.setStackFrame(savedStart);
      }
    }
  }

  /**
   * Get a cloned Iterator that is reset to the beginning
   * of the query.
   *
   * @return A cloned NodeIterator set of the start of the query.
   */
  public DTMIterator cloneWithReset() throws CloneNotSupportedException {

    ChildTestIterator clone = (ChildTestIterator) super.cloneWithReset();

    clone.resetProximityPositions();

    return clone;
  }


}
